Semiconductor devices and method of forming the same

ABSTRACT

Semiconductor devices and methods of forming the semiconductor device are provided, the semiconductor devices including a first dielectric layer on a substrate, and a second dielectric layer on the first dielectric layer. The first dielectric layer has a carbon concentration lower than the second dielectric layer.

PRIORITY STATEMENT

This U.S. non-provisional patent application claims the benefit ofpriority under 35 U.S.C. §119 of Korean Patent Application No.2008-48138, filed on May 23, 2008 in the Korean Intellectual PropertyOffice, which are herein incorporated by reference in their entirety.

BACKGROUND

1. Field

Example embodiments relate to semiconductor devices and/or methods offorming the same.

2. Description of Art

In semiconductor devices, a dielectric layer may be used as a gateinsulating layer of a transistor or a capacitor insulating layer. Inorder for the dielectric layer to effectively function as a gateinsulating layer or a capacitor insulating layer, the dielectric layerhas to exhibit an adequate capacitance. Capacitance is proportional to adielectric constant and an area of a dielectric layer, and is ininversely proportional to a thickness of a dielectric layer.

SUMMARY

Example embodiments relate to semiconductor devices and methods offorming the same.

A method of forming a semiconductor device according to exampleembodiments includes forming a first dielectric layer on a substrate andforming a second dielectric layer on the first dielectric layer. Acarbon concentration in the first dielectric layer may be lower than acarbon concentration of the second dielectric layer.

Example embodiments provide a semiconductor device. The device mayinclude a first dielectric layer on a substrate and a second dielectriclayer on the first dielectric layer. A carbon concentration in the firstdielectric layer may be lower than a carbon concentration of the seconddielectric layer.

BRIEF DESCRIPTION OF THE FIGURES

Example embodiments will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings. FIGS. 1A, 1B, 2A, 2B, 3A, 3B and 4-8 represent non-limiting,example embodiments as described herein.

FIG. 1A is a view of a semiconductor device according to exampleembodiments;

FIG. 1B is an enlarged view of region “A” of the semiconductor deviceshown in FIG. 1A;

FIG. 2A is a view of a semiconductor device according to exampleembodiments;

FIG. 2B is an enlarged view of region “B” of the semiconductor deviceshown in FIG. 2A;

FIG. 3A is a view of a semiconductor device according to exampleembodiments;

FIG. 3B is an enlarged view of region “C” of the semiconductor deviceshown in FIG. 3A; and

FIGS. 4 through 8 are views illustrating a method of forming asemiconductor device according to example embodiments.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Example embodiments of the present invention now will be described morefully hereinafter with reference to the accompanying drawings, in whichembodiments of the invention are shown. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art. Inthe drawings, the size and relative sizes of layers and regions may beexaggerated for clarity. Like numbers refer to like elements throughout.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed itemsand may be abbreviated as “/.”

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first region/layer could be termeda second region/layer, and, similarly, a second region/layer could betermed a first region/layer without departing from the teachings of thedisclosure.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Embodiments of the present invention may be described with reference tocross-sectional illustrations, which are schematic illustrations ofidealized embodiments of the present invention. As such, variations fromthe shapes of the illustrations, as a result, for example, ofmanufacturing techniques and/or tolerances, are to be expected. Thus,embodiments of the present invention should not be construed as limitedto the particular shapes of regions illustrated herein, but are toinclude deviations in shapes that result from, for example,manufacturing. For example, a region illustrated as a rectangle may haverounded or curved features. Thus, the regions illustrated in the figuresare schematic in nature and are not intended to limit the scope of thepresent invention.

In the drawings, the thickness of layers and regions are exaggerated forclarity. It will also be understood that when an element such as alayer, region or substrate is referred to as being “on” or “onto”another element, it may lie directly on the other element or interveningelements or layers may also be present. Like reference numerals refer tolike elements throughout the specification.

Spatially relatively terms, such as “beneath,” “below,” “above,”“upper,” “top,” “bottom” and the like, may be used to describe anelement and/or feature's relationship to another element(s) and/orfeature(s) as, for example, illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use and/or operation in additionto the orientation depicted in the figures. For example, when the devicein the figures is turned over, elements described as below and/orbeneath other elements or features would then be oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly. As used herein, “height” refers toa direction that is generally orthogonal to the faces of a substrate.

Example embodiments relate to semiconductor devices and/or methods offorming the same.

FIG. 1A is a view of a semiconductor device according to exampleembodiments. FIG. 1B is an enlarged view of region “A” of thesemiconductor device shown in FIG. 1A.

Referring to FIGS. 1A and 1B, a semiconductor device according toexample embodiments will now be described.

A gate electrode 30 may be provided on (or over) a substrate 10. Thesubstrate 10 may be a single crystalline silicon layer,silicon-on-insulator (SOI) or a polysilicon layer. However, exampleembodiments are not limited thereto. The substrate 10 may include aconductive region and/or an insulating region. For example, thesubstrate 10 may include an impurity region including source/drainregions. The gate electrode 30 may include a conductive material. Forexample, the gate electrode 30 may include a polysilicon having dopants.

A dielectric layer 22 may be provided between the substrate 10 and thegate electrode 30. The dielectric layer 22 may be a layer having a highdielectric constant. The dielectric layer 22 may be a metal oxide layer,a metal silicon oxide layer and/or a metal silicon oxynitride layerincluding at least one element selected from the group consisting ofhafnium (Hf), zirconium (Zr), aluminum (Al), titanium (Ti), lanthanum(La), yttrium (Y), gadolinium (Gd), tantalum (Ta) and combinationsthereof. The dielectric layer 22 may have a non-uniform profile of acarbon concentration throughout the dielectric layer 22. The dielectriclayer 22 may have the lowest carbon concentration at a region adjacentto the substrate 10. For example, the dielectric layer 22 may have thehighest carbon concentration at a center part of the dielectric layer 22and the lowest carbon concentration at an edge of the dielectric layer22. In another example, the dielectric layer 22 may have a higher carbonconcentration in the region farthest apart from the substrate 10 (e.g.,the region of the dielectric layer 22 near the surface contacting thegate electrode 30.

An oxide layer 11 may be provided between the substrate 10 and thedielectric layer 22. The oxide layer 11 may be a silicon oxide layer, asilicon oxynitride layer or combinations thereof. The oxide layer 11 mayhave a thickness smaller than the dielectric layer 22. For example, athickness ratio of the oxide layer 11 to the dielectric layer 22 may beabout 1:1.5 to about 1:3 (thickness of the oxide layer:thickness of thedielectric layer).

FIG. 2A is a view of a semiconductor device according to exampleembodiments. FIG. 2B is an enlarged view of region “B” of thesemiconductor device shown in FIG. 2A.

Referring to FIGS. 2A and 2B, a semiconductor device according toexample embodiments will be described.

A gate electrode 30 may be provided onto a substrate 10. A firstdielectric layer 24 and a second dielectric layer 26 may be providedbetween the substrate 10 and the gate electrode 30. The first and seconddielectric layers 24 and 26 may have substantially high dielectricconstants. The first dielectric constant 24 may be disposed on thesubstrate 10, and the second dielectric layer 26 may be disposed on thefirst dielectric layer 24.

The first dielectric layer 24 is a layer having a substantially highdielectric constant. The first dielectric layer 24 may be a metal oxidelayer, a metal silicon oxide layer and/or a metal silicon oxynitridelayer including at least one selected from the group consisting of Hf,Zr, Al, Ti, La, Y, Gd, Ta and combinations thereof.

The second dielectric layer 26 is a layer having a substantially highdielectric constant. The second dielectric layer 26 may be a metal oxidelayer, a metal silicon oxide layer and/or a metal silicon oxynitridelayer including at least one selected from the group consisting of Hf,Zr, Al, Ti, La, Y, Gd, Ta and combinations thereof. The carbonconcentration in the second dielectric layer 26 may be higher than thecarbon concentration in the first dielectric layer 24. The carbonconcentration in the second dielectric layer 26 may be about 3% or less.

The first and second dielectric layers 24 and 26 may include differentmaterials, respectively. For example, the first dielectric layer 24 mayinclude a metal silicon oxide, and the second dielectric layer 26 mayinclude a metal oxide. Alternatively, the first and second dielectriclayers 24 and 26 may be a metal oxide layer or a metal silicon oxidelayer, respectively, including different metals.

An oxide layer 11 may be provided between the substrate 10 and the firstdielectric layer 24. The oxide layer 11 may be a silicon oxide layer, asilicon oxynitride layer or combinations thereof. The oxide layer 11 mayhave a thickness smaller than the dielectric layers 24 and 26. Forexample, the oxide layer 11 have a thickness smaller than the dielectriclayer 24, the dielectric layer 26 or the sum of the dielectric layer 24and 26.

FIG. 3A a view of a semiconductor device according to exampleembodiments. FIG. 3B is an enlarged view of region “C” of thesemiconductor device shown in FIG. 3A.

Referring to FIGS. 3A and 3B, a semiconductor device according toexample embodiments will be described.

A gate electrode 30 may be provided onto a substrate 10. The substrate10 may include a conductive region and/or an insulating layer.

First, second and third dielectric layers 24, 26 and 28 may be providedbetween the substrate 10 and the gate electrode 30. The first dielectriclayer 24 may be adjacent to the substrate 10, and the third dielectriclayer 28 may be adjacent to the gate electrode 30. The second dielectriclayer 26 may be disposed between the first dielectric layer 24 and thethird dielectric layer 28.

The third dielectric layer 28 is a layer having a substantially highdielectric constant. The third dielectric layer 28 may be a metal oxidelayer, a metal silicon oxide layer and/or a metal silicon oxynitridelayer including at least one selected from the group consisting of Hf,Zr, Al, Ti, La, Y, Gd, Ta and combinations thereof. A carbonconcentration in the third dielectric layer 28 may be lower than acarbon concentration in the second dielectric layer 26.

An oxide layer 11 may be provided between the substrate 10 and the firstdielectric layer 24. The oxide layer 11 may be a silicon oxide layer, asilicon oxynitride layer or combinations thereof. The oxide layer 11 mayhave a thickness smaller than a sum of thicknesses of the dielectriclayers 24, 26 and 28.

FIGS. 4 through 8 are views illustrating a method of forming asemiconductor device according to example embodiments.

Referring to FIGS. 4 through 8, a method of forming a semiconductordevice according example embodiments will now be described. FIGS. 4through 8 are diagrams of a gas injection if a dielectric layeraccording to example embodiments is formed by an atomic layer deposition(ALD).

Referring to FIGS. 4, 1A and 1B, a method of forming a semiconductordevice according to example embodiments will be described.

A substrate 10 is loaded in a reactor. A first metal source is injectedinto the reactor. The first metal source may be an inorganic metalcompound. The first metal source may be a metal halide inorganiccompound including at least one metal selected from the group consistingof Hf, Zr, Al, Ti, La, Y, Gd, Ta and combinations thereof. The metalhalide inorganic compound may not include carbon. The metal halideinorganic compound may include at least one halogen atom. The firstmetal source may be HfCl₄, ZrCl₄, ZrBr₄, HfI₄, ZrI₄ or combinationsthereof. After the first metal source is injected, a purge gas may beinjected. The purge gas may purge any of the first metal source whichremains and is not absorbed on the substrate to the outside of thereactor.

A first oxidation gas may be injected into the reactor. The firstoxidation gas may be ozone (O₃), an oxygen (O) radical, water (H₂O),hydrogen peroxide (H₂O₂) or combinations thereof. After the firstoxidation gas is injected, a purge gas may be injected.

A second metal source is injected in the reactor. The second metalsource may be an organic metal compound including at least one of Hf,Zr, Al, Ti, La, Y, Gd, Ta or combinations thereof. The second metalsource may be a metal compound including at least one carbon atom. Forexample, the second metal source may be at least one of Hf[N(CH₃)₂]₄,Hf[N(CH₃)(C₂H₅)]₄, Hf[N(C₂H₅)]₄, Hf[OCH₃]₄, Hf[OC₂H₅]₄, Zr[N(CH₃)₂]₄,Zr[N(CH₃)(C₂H₅)]₄, Zr[N(C₂H₅)]₄, Zr[OCH₃]₄, Zr[OC₂H₅]₄ or combinationsthereof. After the second metal source is injected, a purge gas may beinjected.

The first metal source and the second metal source may be metalcompounds including a same metal. For example, the first metal sourcemay be a hafnium compound not including carbon, and the second metalsource may be a hafnium compound including carbon.

A third oxidation gas may be injected into the reactor. The thirdoxidation gas may be O₃, O radical, H₂O, H₂O₂ or combinations thereof.After the third oxidation gas is injected, a purge gas may be injected.The dielectric layer 22 may be formed to have the lowest carbonconcentration at (or in) a region adjacent to the substrate 10.

After second metal source is injected, the first metal source, the firstoxidation gas and a purge gas may be injected (or removed). Thedielectric layer 22 may have the highest carbon concentration at acentral part. A carbon concentration at both edges of the dielectriclayer 22 may be lower than the carbon concentration at the central partof the dielectric layer 22.

The first and second metal sources, and the first and third oxidationgases may be injected several times (or repeatedly). The second metalsource and the third oxidation gas may be injected several times afterthe first metal source and the first oxidation gas are injected severaltimes. For example, the first and second metal sources, and the firstand third oxidation gases may be injected in the following order: thefirst metal source_(l)→the first oxidation gas_(m)→the second metalsource_(n)→the third oxidation gas_(o) (wherein l, m, n and o representa number of injections and are a natural number (or integer) of 1 ormore). After the first metal source and the first oxidation gas arealternately injected several times, the second metal source and thethird oxidation gas may be alternately injected several times. Forexample, the first and second metal sources, and the first and thirdoxidation gases may be injected in the following order: (the first metalsource→the first oxidation gas)_(x)→(the second metal source→the thirdoxidation gas)_(y) (wherein x and y represent a number of injections andare a natural number (or integer) of 1 or more). The number of timeseach step is repeated may be controlled depending on desired features(e.g., thickness, concentration, etc.) of the layer to be formed.

A dielectric layer 22 may be formed by injecting the first and secondmetal sources, and the first and third oxidation gases. The dielectriclayer 22 may be a metal oxide layer or a metal silicon oxide layer. Thedielectric layer 22 may be formed such that a region adjacent to thesubstrate 10 has the lowest carbon concentration.

A subsequent process may be performed during or after formation of thedielectric layer 22. In the subsequent process, a portion of the carbonslocated on an upper portion of the dielectric layer 22 may be diffusedinto a lower portion of the dielectric layer 22. An oxide layer 11 maybe formed between the dielectric layer 22 and the substrate 10 dependingon conditions of the subsequent process. The oxide layer 11 may be atleast one of a silicon oxide layer, a silicon oxynitride or combinationsthereof.

A gate electrode 30 is formed on the dielectric layer 22. A polysiliconlayer (not shown) is formed on the dielectric layer 22. The polysiliconlayer is patterned to form the gate electrode 30. However, a method offorming the gate electrode 30 is not limited to the aforementionedmethod.

Referring to FIGS. 5, 1A and 1B, another method of forming asemiconductor device according to example embodiments will now bedescribed. A substrate 10 is loaded in a reactor. A first metal sourcemay be injected into the reactor. The first metal source may be a metalhalide inorganic compound including at least one selected from the groupconsisting of Hf, Zr, Al, Ti, La, Y, Gd, Ta and combinations thereof.For example, the first metal source may be at least one of HfCl₄, ZrCl₄,ZrBr₄, HfI₄, ZrI₄ or combinations thereof. After the first metal sourceis injected, a purge gas may be injected.

A first oxidation gas may be injected into the reactor. The firstoxidation gas may be at least one of O₃, O radical, H₂O, H₂O₂ orcombinations thereof. After the first oxidation gas is injected, a purgegas may be injected.

An inorganic silicon compound may be injected into the reactor. Theinorganic silicon compound may be a silicon compound not includingcarbon. The inorganic silicon compound may be injected in the form of agas. The inorganic silicon compound may be halide silane or halidedisilane including at least one of SiCl₄, SiCl₆, SiCl₂H₄, SiF₄ orcombinations thereof. After the inorganic silicon compound is injectedinto the reactor, a purge gas may be injected.

A second oxidation gas may be injected into the reactor. The secondoxidation gas may be at least one of O₃, O radical, H₂O, H₂O₂ orcombinations thereof. After the second oxidation gas is injected, apurge gas may be injected.

The first metal source, the first oxidation gas, the inorganic siliconcompound and the second oxidation gas may be injected several times.After the first metal source and the first oxidation gas are injectedseveral times, the inorganic silicon compound and the second oxidationgas may be injected several times. For example, the first metal source,the first and second oxidation gases, and the inorganic silicon compoundmay be injected in the following order: the first metal source_(l)→thefirst oxidation gas_(m)→the inorganic silicon compound_(n)→the secondoxidation gas_(o) (wherein l, m, n and o represent a number ofinjections and are a natural number (or integer) of 1 or more). Afterthe first metal source and the first oxidation gas are alternatelyinjected several times, the inorganic silicon compound and the secondoxidation gas may be alternately injected several times. For example,the first metal source, the first and second oxidation gases, and theinorganic silicon compound may be injected in the following order: (thefirst metal source→the first oxidation gas)_(x)→(the inorganic siliconcompound→the second oxidation gas)_(y) (wherein x and y represent anumber of injections and are a natural number (or integer) of 1 ormore). The number of times the first metal source is injected may begreater than the number of times the inorganic silicon compound isinjected. An alternate injection of the first metal source, the firstoxidation gas, the inorganic silicon compound and the second oxidationgas may be repeatedly performed. For example, a sequence (q) of thefirst metal source, the first oxidation gas, the inorganic siliconcompound and the second oxidation gas may be repeated in the followingorder: (the first metal source_(l)→the first oxidation gas_(m)→theinorganic silicon compound_(n)→the second oxidation gas_(o))_(q)(wherein l, m, n, o and q represent a number of repetitions and are anatural number (or integer) of 1 or more). An alternate sequence (z) ofthe first metal source, the first oxidation gas, the inorganic siliconcompound and the second oxidation gas may be repeated in the followingorder: {(the first metal source→the first oxidation gas)_(x)→(theinorganic silicon compound→the second oxidation gas)_(y)}_(z) (whereinx, y and z represent a number of repetitions and are a natural number(or integer) of 1 or more). The number of times each step is repeatedmay be controlled depending on the desired features of the layer to beformed.

A second metal source may be injected in the reactor. The second metalsource may be an organic metal compound including at least one metalselected from the group consisting of Hf, Zr, Al, Ti, La, Y, Gd, Ta orcombinations thereof. The organic metal compound may be a metal compoundincluding at least one carbon atom. For example, the second metal sourcemay be at least one of Hf[N(CH₃)₂]₄, Hf[N(CH₃)(C₂H₅)]₄, Hf[N(C₂H₅)]₄,Hf[OCH₃]₄, Hf[OC₂H₅]₄, Zr[N(CH₃)₂]₄, Zr[N(CH₃)(C₂H₅)]₄, Zr[N(C₂H₅)]₄,Zr[OCH₃]₄, Zr[OC₂H₅]₄ or combinations thereof. After the second metalsource is injected, a purge gas may be injected.

The first metal source and the second metal source may be metalcompounds including a same metal. For example, the first metal sourcemay be a hafnium compound not including carbon, and the second metalsource may be a hafnium compound including carbon.

A third oxidation gas may be injected into the reactor. The thirdoxidation gas may be at least one of O₃, O radical, H₂O, H₂O₂ orcombinations thereof. After the third oxidation gas is injected, a purgegas may be injected.

An organic silicon compound may be injected into the reactor. Theorganic silicon compound may be a silicon compound including at leastone carbon atom. The organic silicon compound may be a compound havingan alkyl amino group including SiH_(n)(NR₁R₂)_(4-n) (wherein 0≦n<4). R₁and R₂ may each independently be at least one selected from a groupconsisting of an alkyl, an allyl and combinations thereof. After theorganic silicon compound is injected, a purge gas may be injected intothe reactor.

A fourth oxidation gas may be injected into the reactor. The fourthoxidation gas may be at least one of O₃, O radical, H₂O, H₂O₂ orcombinations thereof. After the fourth oxidation gas is injected, apurge gas may be injected.

The second metal source, the third oxidation gas, the organic siliconcompound and the fourth oxidation gas may be injected several times.After the second metal source and the third oxidation gas are injectedseveral times, the organic silicon compound and the fourth oxidation gasmay be injected several times. For example, the second metal source, thethird and fourth oxidation gases, and the organic silicon compound maybe injected in the following order: the second metal source_(l)→thethird oxidation gas_(m)→the organic silicon compound_(n)→the fourthoxidation gas_(o) (wherein l, m, n and o represent a number ofinjections and are a natural number (or integer) of 1 or more). Afterthe second metal source and the third oxidation gas are alternatelyinjected several times, the organic silicon compound and the fourthoxidation gas may be alternately injected several times. For example,the second metal source, the third and fourth oxidation gases, and theorganic silicon compound may be injected in the following order: (thesecond metal source_(l)→the third oxidation gas)_(x)→(the organicsilicon compound→the fourth oxidation gas)_(y) (wherein x and yrepresent a number of injections and are a natural number (or integer)of 1 or more). The number of times the second metal source is injectedmay be greater than the number of times the organic silicon compound isinjected. An alternate injection of the second metal source, the thirdoxidation gas, the organic silicon compound and the fourth oxidation gasmay be repeatedly performed. For example, a sequence (q) of the secondmetal source, the third oxidation gas, the organic silicon compound andthe fourth oxidation gas may be repeated in the following order: (thesecond metal source_(l)→the third oxidation gas_(m)→the organic siliconcompound_(n)→the fourth oxidation gas_(o))_(q) (wherein l, m, n, o and qrepresent a number of repetitions and are natural number (or integer) of1 or more). An alternate sequence (z) of the second metal source, thethird oxidation gas, the organic silicon compound and the fourthoxidation gas may be repeated in the following order: {(the second metalsource→the third oxidation gas)_(x)→(the organic silicon compound→thefourth oxidation gas)_(y)}_(z) (wherein x, y and z represent a number ofrepetitions and are natural number (or integer) of 1 or more). Thenumber of times each step is repeated may be controlled depending ondesired features of the layer to be formed.

A dielectric layer 22 may be formed by injection of the first and secondmetal sources, the first, second, third and fourth oxidation gases, theinorganic silicon compound, and the organic silicon compound. Thedielectric layer 22 may be a metal silicon oxide layer. The dielectriclayer 22 may be formed such that a region adjacent to the substrate 10has the lowest carbon concentration.

A subsequent process may be performed during or after formation of thedielectric layer 22. An oxide layer 11 may be formed between thedielectric layer 22 and the substrate 10 depending on conditions of thesubsequent process. The oxide layer 11 may be a silicon oxide layer, asilicon oxynitride or combinations thereof.

A gate electrode 30 may be formed on the dielectric layer 22. Afterpolysilicon layer is formed on the dielectric layer 22, the polysiliconlayer is patterned to form the gate electrode 30. However, a method offorming the gate electrode 30 is not limited to an aforementionedmethod.

Referring to FIGS. 4, 2A and 2B, another method of forming asemiconductor device according to example embodiments will be described.A substrate 10 is loaded in a reactor. A first metal source may beinjected into the reactor. The first metal source may be metal halideinorganic compound including at least one metal selected from the groupconsisting of at least one of Hf, Zr, Al, Ti, La, Y, Gd, Ta andcombinations thereof. For example, the first metal source may be HfCl₄,ZrCl₄, ZrBr₄, HfI₄, ZrI₄ or combinations thereof. After the first metalsource is injected, a purge gas may be injected.

A first oxidation gas may be injected into the reactor. The firstoxidation gas may be at least one of O₃, O radical, H₂O, H₂O₂ orcombinations thereof. After the first oxidation gas is injected, a purgegas may be injected. A first dielectric layer 24 may be formed on thesubstrate 10 by an injection of the first metal source and the firstoxidation gas. The first dielectric layer 24 may be a metal oxide layer.

The first metal source and the first oxidation gas may be injectedseveral times. For example, after the first metal source is injectedseveral times, the first oxidation gas may be injected several times(the first metal source_(l)→the first oxidation gas_(m)) (wherein l andm represent a number of injections and are natural number (or integerof) 1 or more). In another example, the first metal source and the firstoxidation gas may be alternately injected several times (the first metalsource→the first oxidation gas)_(x) (wherein x represents a number ofinjection and is natural number (or integer) of 1 or more). A ratio ofmetal to oxygen in the layer may differ depending on the number of timesthe first metal source and the first oxidation gas are injected. Athickness of the first dielectric layer 24 may be controlled bycontrolling the number of times the first metal source and the firstoxidation gas are injected.

The first dielectric layer 24 may be formed by a method capable ofcontrolling a carbon concentration in the layer. For example, the firstdielectric layer 24 may be formed by a chemical vapor deposition and maybe formed using a precursor not including carbon. In another example,the first dielectric layer 24 may use an inorganic metal compound as aprecursor and may be formed with a lower carbon concentration bycontrolling the first oxidation gas or an addition gas. If the firstdielectric layer 24 is formed, a portion of the organic metal compoundmay be injected but a carbon concentration in the layer may be lower bycontrolling the first oxidation gas or an addition gas. The firstoxidation gas may be O₃, and the addition gas may include nitrogen.

After the first metal source and the first oxidation gas are injected, asubsequent process may be performed. An oxide layer 11 may be formedbetween the first dielectric layer 24 and the substrate 10 during thesubsequent process. Depending on conditions of the subsequent process,the oxide layer 11 may be at least one of a silicon oxide layer, asilicon oxynitride or combinations thereof.

A second metal source may be injected in the reactor. The second metalsource may be an organic metal compound including at least one of Hf,Zr, Al, Ti, La, Y, Gd, Ta or combinations thereof. The organic metalcompound may be a metal compound including at least one carbon atom. Forexample, the second metal source may be at least one of Hf[N(CH₃)₂]₄,Hf[N(CH₃)(C₂H₅)]₄, Hf[N(C₂H₅)]₄, Hf[OCH₃]₄, Hf[OC₂H₅]₄, Zr[N(CH₃)₂]₄,Zr[N(CH₃)(C₂H₅)]₄, Zr[N(C₂H₅)]₄, Zr[OCH₃]₄, Zr[OC₂H₅]₄ or combinationsthereof. After the second metal source is injected, a purge gas may beinjected.

A third oxidation gas is injected into the reactor. The third oxidationgas may be at least one of O₃, O radical, H₂O, H₂O₂ or combinationsthereof. After the third oxidation gas is injected, a purge gas may beinjected.

The second metal source and the third oxidation gas may be injectedseveral times. After the second metal source is injected several times,the third oxidation gas may be injected several times. For example, thesecond metal source and the third oxidation gas may be injected in thefollowing order: the second metal source_(l)→the third oxidation gas_(m)(wherein l and m represent a number of injections and are natural number(or integer) of 1 or more). Alternatively, the second metal source andthe third oxidation gas may be alternately injected several times. Forexample, the second metal source and the third oxidation gas may beinjected in the following order: (the second metal source→the thirdoxidation gas)_(x) (wherein x is represents a number of injections andis natural number (or integer) of 1 or more). The number of times eachstep is performed may be controlled (or adjusted for) by desiredfeatures of the dielectric layer.

The second dielectric layer 26 is formed on the first dielectric layer24 by injecting the second metal source and the third oxidation gas. Thesecond dielectric layer 26 may be a metal oxide layer.

Alternatively, the second dielectric layer 26 may be formed using awell-known method of forming a thin film including a chemical vapordeposition (CVD) method, a metal organic chemical vapor deposition(MOCVD) method or similar method.

A subsequent process may be performed before or after formation of thesecond dielectric layer 26. An oxide layer 11 may be formed between thefirst dielectric layer 24 and the substrate 10 depending on conditionsof the subsequent process. The oxide layer 11 may be at least one of asilicon oxide layer, a silicon oxynitride layer or combinations thereof.

A gate electrode 30 is formed on the second dielectric layer 26. Afterpolysilicon layer (not shown) is formed on the second dielectric layer26, the polysilicon layer is patterned to form the gate electrode 30.However, a method of forming the gate electrode 30 is not limited to anaforementioned method.

Referring to FIGS. 6, 2A and 2B, another method of forming asemiconductor device according to example embodiments will be described.A substrate 10 is loaded in a reactor. A first metal source and a firstoxidation gas are injected into the reactor. After the first metalsource is injected and after the first oxidation gas is injected, apurge gas may be injected.

The first metal source may be a metal halide inorganic compoundincluding at least one metal selected from the group consisting of Hf,Zr, Al, Ti, La, Y, Gd, Ta and combinations thereof. For example, thefirst metal source may be at least one of HfCl₄, ZrCl₄, ZrBr₄, HfI₄,ZrI₄ or combinations thereof. The first oxidation gas may be at leastone of O₃, O radical, H₂O, H₂O₂ or combinations thereof.

An inorganic silicon compound is injected into the reactor. Theinorganic silicon compound is a silicon compound not including carbonand may be injected in the form of a gas. The inorganic silicon compoundmay be halide silane or halide disilane including at least one of SiCl₄,SiCl₆, SiCl₂H₄, SiF₄ and combinations thereof. After the inorganicsilicon compound is injected into the reactor, a purge gas may beinjected.

A second oxidation gas is injected into the reactor. The secondoxidation gas may be at least one of O₃, O radical, H₂O, H₂O₂ orcombinations thereof. After the second oxidation gas is injected, apurge gas may be injected.

The first metal source, the first and second oxidation gases, and theinorganic silicon compound may be injected several times. After thefirst metal source is injected several times, the inorganic siliconcompound may be injected several times. For example, the first metalsource, the first and second oxidation gases, and the inorganic siliconcompound may be injected in the following order: the first metalsource_(l)→the first oxidation gas_(m)→the inorganic siliconcompound_(n)→the second oxidation gas_(o) (wherein l, m, n and orepresent a number of injections and are natural number (or integer) of1 or more). Alternatively the first metal source and the inorganicsilicon compound are alternately injected several times. For example,the first metal source, the first and second oxidation gases, and theinorganic silicon compound may be injected in the following order: (thefirst metal source→the first oxidation gas)_(x)→(the inorganic siliconcompound→the second oxidation gas)_(y) (wherein x and y represent anumber of injection and are natural number (or integer) of 1 or more).The number of times the first metal source is injected may be greaterthan the number of times the inorganic silicon compound is injected. Analternate injection of the first metal source, the first oxidation gas,the inorganic silicon compound and the second oxidation gas may berepeatedly performed. For example, a sequence (q) of the first metalsource, the first oxidation gas, the inorganic silicon compound and thesecond oxidation gas may be repeated in the following order: (the firstmetal source_(l)→the first oxidation gas_(m)→the inorganic siliconcompound_(n)→the second oxidation gas_(o))_(q) (wherein l, m, n, o and qrepresent a number of repetitions and are natural number (or integer) of1 or more). An sequence (z) of the first metal source, the firstoxidation gas, the inorganic silicon compound and the second oxidationgas may be repeated in order of {(the first metal source→the firstoxidation gas)_(x)→(the inorganic silicon compound→the second oxidationgas)_(y)}_(z) (wherein x, y and z represent a number of repetitions andare natural number (or integer) of 1 or more). The number of time eachstep is performed may be controlled depending on desired features of thelayer to be formed.

The first dielectric layer 24 may be formed by injecting the first metalsource and the inorganic silicon compound. The first dielectric layer 24may be a metal silicon oxide layer.

The first dielectric layer 24 may be formed by a method capable ofcontrolling a concentration in the layer. For example, the firstdielectric layer 24 may be formed by a chemical vapor deposition (CVD)and may be formed using a precursor not including carbon. In anotherexample, the first dielectric layer 24 may use an organic metal compoundand/or an organic silicon compound as a precursor and may be formed tohave a lower carbon concentration by controlling the first oxidation gasor an addition gas. The first oxidation gas may be O₃, and the additiongas may include nitrogen.

After the first dielectric layer 24 is formed, a subsequent process maybe performed. During the subsequent process, an oxide layer 11 may beformed between the first dielectric layer 24 and the substrate 10.Depending on conditions of the subsequent process, the oxide layer 11may be at least one of a silicon oxide layer, a silicon oxynitride orcombinations thereof.

A second dielectric layer 26 is formed on the first dielectric layer 24.The second dielectric layer 26 may be a metal oxide layer. The seconddielectric layer 26 may be formed by injecting a second metal source, athird oxidation gas and a purge gas into the reactor. The second metalsource and the third oxidation gas may be injected several times.

The second metal source may be an organic metal compound including atleast one of Hf, Zr, Al, Ti, La, Y, Gd, Ta or combinations thereof. Theorganic metal compound may be a metal compound including at least onecarbon atom. For example, the second metal source may be at least one ofHf[N(CH₃)₂]₄, Hf[N(CH₃)(C₂H₅)]₄, Hf[N(C₂H₅)]₄, Hf[OCH₃]₄, Hf[OC₂H₅]₄,Zr[N(CH₃)₂]₄, Zr[N(CH₃)(C₂H₅)]₄, Zr[N(C₂H₅)]₄, Zr[OCH₃]₄, Zr[OC₂H₅]₄ orcombinations thereof. After the second metal source is injected, a purgegas may be injected. The third oxidation gas may be at least one of O₃,O radical, H₂O, H₂O₂ or combinations thereof. After the third oxidationgas is injected, a purge gas may be injected.

After the second dielectric layer 26 is formed, a subsequent process maybe performed. An oxide layer 11 may be formed between the firstdielectric layer 24 and the substrate 10 depending on conditions of thesubsequent process. The oxide layer 11 may be a silicon oxide layer, asilicon oxynitride or combinations thereof.

A gate electrode 30 may be formed on the second dielectric layer 26.After polysilicon layer is formed on the second dielectric layer 26, thepolysilicon is patterned to form the gate electrode 30. However, amethod of forming the gate electrode 30 is not limited to anaforementioned method.

Referring to FIGS. 7, 2A and 2B, another method of forming asemiconductor device according to example embodiments will be described.A substrate 10 is loaded in a reactor. A first metal source may beinjected into the reactor. The first metal source may be a metal halideinorganic compound including at least one of Hf, Zr, Al, Ti, La, Y, Gd,Ta or combinations thereof. A first oxidation gas may be injected intothe reactor. The first oxidation gas may be at least one of O₃, Oradical, H₂O, H₂O₂ or combinations thereof. After the first metal sourceand the first oxidation gas are injected, a purge gas may be injected. Afirst dielectric layer 24 may be formed on the substrate by injectingthe first metal source and the first oxidation gas. The first dielectriclayer 24 may be a metal oxide layer.

A second metal source and a third oxidation gas are injected in thereactor. The second metal source may be an organic metal compoundincluding at least one of Hf, Zr, Al, Ti, La, Y, Gd, Ta or combinationsthereof. The third oxidation gas may be at least one of O₃, O radical,H₂O, H₂O₂ or combinations thereof. After the third oxidation gas isinjected, a purge gas may be injected.

An organic silicon compound may be injected into the reactor. Theorganic silicon compound may be a silicon compound including at leastone carbon atom. The organic silicon compound may be a compound havingalkyl amino group including SiH_(n)(NR₁R₂)_(4-n) (wherein 0≦n<4). R₁ andR₂ may each independently be at least one selected from a groupconsisting of alkyl, allyl and combinations thereof. After the organicsilicon compound is injected, a purge gas may be injected into thereactor.

A fourth oxidation gas may be injected into the reactor. The fourthoxidation gas may be at least one of O₃, O radical, H₂O, H₂O₂ orcombinations thereof. After the fourth oxidation gas is injected, apurge gas may be injected.

The second metal source, the third and fourth oxidation gases, and theorganic silicon compound may be injected several times. After the secondmetal source is injected several times, the organic silicon compound maybe injected several times. For example, the second metal source, thethird and fourth oxidation gases, and the organic silicon compound maybe injected in the following order: the second metal source_(l)→thethird oxidation gas_(m)→the organic silicon compound_(n)→the fourthoxidation gas_(o) (wherein l, m, n and o represent a number ofinjections and are natural number (or integer) of 1 or more).Alternatively, the second metal source and the organic silicon compoundare alternately injected several times. For example, the second metalsource, the third and fourth oxidation gases, and the organic siliconcompound may be injected in the following order: (the second metalsource→the third oxidation gas)_(x)→(the organic silicon compound→thefourth oxidation gas)_(y) (wherein x and y represent a number ofinjection and are natural number (or integer) of 1 or more). The numberof times the second metal source is injected may be greater than thenumber of times the organic silicon compound is injected. An alternateinjection of the second metal source, the third oxidation gas, theorganic silicon compound and the fourth oxidation gas may be repeatedlyperformed. For example, the second metal source, the third oxidationgas, the organic silicon compound and the fourth oxidation gas may berepeated in the following orders: (the second metal source_(l)→the thirdoxidation gas_(m)→the organic silicon compound_(n)→the fourth oxidationgas_(o))_(q) (wherein q represents a number of repetitions and arenatural number (or integer) of 1 or more) or {(the second metalsource→the third oxidation gas)_(x)→(the organic silicon compound→thefourth oxidation gas)_(y)}_(z) (wherein x, y and z represent a number ofrepetitions and are natural number (or integer) of 1 or more). Thenumber of times the second metal source and the organic silicon compoundare injected may be controlled depending on features of the layer.

A second dielectric layer 26 may be formed by injecting the second metalsource, the third gas, the organic silicon compound and the fourthoxidation gas. The second dielectric layer 26 may be a metal siliconoxide layer.

After the first dielectric layer 24 and/or the second dielectric layer26 are formed, a subsequent process may be performed. An oxide layer 11may be formed between the first dielectric layer 24 and the substrate 10depending on conditions of the subsequent process. The oxide layer 11may be at least one of a silicon oxide layer, a silicon oxynitride orcombinations thereof.

A gate electrode 30 is formed on the second dielectric layer 26. Afterpolysilicon layer (not shown) is formed on the second dielectric layer26, the polysilicon layer is patterned to form the gate electrode 30.However, a method of forming the gate electrode 30 is not limited to anaforementioned method.

Referring to FIGS. 5, 2A and 2B, another method of forming asemiconductor device according to example embodiments will be described.A substrate 10 may be loaded in a reactor. A first dielectric layer 24may be formed on the substrate 10.

The first dielectric layer 24 may be formed by injecting a first metalsource, a first oxidation gas, an inorganic silicon compound and asecond oxidation gas into the reactor. The first metal source, the firstoxidation gas, the inorganic silicon compound and the second oxidationgas may be injected several times, respectively.

The first metal source may be a metal halide inorganic compoundincluding at least one metal selected from the group consisting of Hf,Zr, Al, Ti, La, Y, Gd, Ta and combinations thereof. After the firstmetal source is injected, a purge gas may be injected.

The first oxidation gas may be at least one of O₃, O radical, H₂O, H₂O₂or combinations thereof. After the first oxidation gas is injected, apurge gas may be injected. The inorganic metal compound may be a siliconcompound not including carbon. After the inorganic metal compound isinjected, a purge gas may be injected. A dielectric layer 24 formed bythe method described above. The dielectric layer 24 may be a metalsilicon oxide layer.

A second dielectric layer 26 may be formed on the substrate includingthe first dielectric layer 24. The second dielectric 26 may be formed byinjecting a second metal source, a third oxidation gas, an organicsilicon compound and a fourth oxidation gas into the reactor. The seconddielectric layer 26 may be formed by the method described above. Thesecond dielectric layer 26 may be a metal silicon oxide layer.

The second metal source may be an organic metal compound including atleast one metal selected from the group consisting of Hf, Zr, Al, Ti,La, Y, Gd, Ta and combinations thereof. After the second metal source isinjected, a purge gas may be injected. The third oxidation gas may beinjected in the reactor. The first and second metal sources may becompounds including different metals.

After the third oxidation gas is injected, an organic silicon compoundis injected into the reactor. The organic silicon compound may be asilicon compound including at least one carbon atom. The organic siliconcompound may be silane or disilane including at least one carbon atom.The organic silicon compound may be a compound having alkyl amino groupincluding SiH_(n)(NR₁R₂)_(4-n) (wherein 0≦n<4). R₁ and R₂ may eachindependently be at least one selected from a group consisting of alkyl,allyl and combinations thereof. After the organic silicon compound isinjected, a purge gas may be injected into the reactor. A fourth gas isinjected into the reactor. After the fourth oxidation gas is injected, apurge gas may be injected.

After the first dielectric layer 24 and/or the second dielectric layer26 are formed, a subsequent process may be performed. An oxide layer 11may be formed between the first dielectric layer 24 and the substrate 10depending on conditions of the subsequent process. The oxide layer 11may be a silicon oxide layer, a silicon oxynitride layer or combinationsthereof.

A gate electrode 30 is formed on the second dielectric layer 26. Afterpolysilicon layer (not shown) is formed on the second dielectric layer26, the polysilicon layer is patterned to form the gate electrode 30.However, a method of forming the gate electrode 30 is not limited to anaforementioned method.

Referring to FIGS. 8, 3A and 3B, another method of forming asemiconductor device according to example embodiments will be described.A substrate 10 is loaded in a reactor. A first metal source and a firstoxidation gas are injected into the reactor. The first metal source maybe a metal halide inorganic compound including at least one of Hf, Zr,Al, Ti, La, Y, Gd, Ta or combinations thereof. After the first oxidationgas and the first oxidation gas are injected, a purge gas may beinjected.

An inorganic silicon compound and a second oxidation gas may be injectedinto the reactor. The inorganic silicon compound may be halide silane orhalide disilane not including carbon. After the inorganic siliconcompound and/or the second oxidation gas are injected, a purge gas maybe injected. The first metal source, the first and second oxidationgases, and the inorganic silicon compound may be injected several times,respectively.

A first dielectric layer 24 may be formed on the substrate 10 byinjecting the first metal source, the first and second oxidation gasesand the inorganic silicon compound. The first dielectric layer 24 may bea metal oxide layer or a metal silicon oxide layer depending on whetheror not the inorganic silicon compound and the second oxidation gas areinjected.

A second metal source and a third oxidation gas are injected into thereactor. After the second metal source and/or the third oxidation gasare injected, a purge gas may be injected.

An organic silicon compound and a fourth oxidation gas may be injected.After the organic silicon compound and the fourth oxidation gas areinjected, a purge gas may be injected. The second metal source, thethird and fourth oxidation gases, and the organic silicon compound maybe injected several times, respectively.

A second dielectric layer 26 may be formed on the first dielectric layer24 by injecting the second metal source, the third and fourth oxidationgases, and the organic silicon compound. The second dielectric layer 26may be a metal oxide layer or a metal silicon oxide layer depending onwhether or not the organic silicon compound and the fourth oxidation gasis injected.

A third metal source is injected into the reactor. The third metalsource may be a metal compound including at least one of Hf, Zr, Al, Ti,La, Y, Gd, Ta or combinations thereof. After the third metal source isinjected, a purge gas may be injected.

A fifth oxidation gas is injected into the reactor. The fifth oxidationgas may be at least one of O₃, O radical, H₂O, H₂O₂ or combinationsthereof. After the fifth oxidation gas is injected, a purge gas may beinjected.

A silicon compound and a sixth oxidation gas may be injected into thereactor. The sixth oxidation gas may be at least one of O₃, O radical,H₂O, H₂O₂ or combinations thereof. After the silicon compound and thesixth oxidation gas are injected, a purge gas may be injected. A thirddielectric layer 26 may be formed on the second dielectric layer 24 byinjecting the third metal source and the fifth oxidation gas.

The third dielectric layer 28 may be a metal oxide layer or a metalsilicon oxide layer depending on whether or not the silicon compound andthe sixth oxidation gas are injected. The third dielectric layer 28 mayhave a different carbon concentration depending on whether the thirdmetal source and the silicon compound include carbon or not.

After the first and second dielectric layers 24 and 26, and/or the thirddielectric layer 28 are formed, a subsequent process may be performed.An oxide layer 11 may be formed between the first dielectric layer 24and the substrate 10 depending on a condition of the subsequent process.The oxide layer 11 may be at least one of a silicon oxide layer, asilicon oxynitride layer or combinations thereof.

A gate electrode 30 is formed on the second dielectric layer 26. After apolysilicon layer (not shown) is formed on the second dielectric layer26, the polysilicon layer is patterned to form the gate electrode 30.However, a method of forming the gate electrode 30 is not limited to anaforementioned method.

The foregoing is illustrative of example embodiments and is not to beconstrued as limiting thereof. Although a few example embodiments havebeen described, those skilled in the art will readily appreciate thatmany modifications are possible in example embodiments withoutmaterially departing from the novel teachings and advantages of thepresent invention. Accordingly, all such modifications are intended tobe included within the scope of this invention as defined in the claims.In the claims, means-plus-function clauses are intended to cover thestructures described herein as performing the recited function, and notonly structural equivalents but also equivalent structures. Therefore,it is to be understood that the foregoing is illustrative of the presentinvention and is not to be construed as limited to the specificembodiments disclosed, and that modifications to the disclosedembodiments, as well as other embodiments, are intended to be includedwithin the scope of the appended claims. The present invention isdefined by the following claims, with equivalents of the claims to beincluded therein.

What is claimed is:
 1. A method of forming a semiconductor device,comprising: forming a first dielectric layer on a substrate; forming asecond dielectric layer on the first dielectric layer; and forming athird dielectric layer on the second dielectric layer, wherein a carbonconcentration in the first dielectric layer and the third dielectriclayer is lower than a carbon concentration in the second dielectriclayer, and a region in the first dielectric layer adjacent to thesubstrate has the lowest carbon concentration.
 2. The method of claim 1,wherein forming the first dielectric layer includes using a first metalsource, and forming the second dielectric layer includes using a secondmetal source.
 3. The method of claim 2, wherein the first metal sourceand the second metal source include a same metal.
 4. The method of claim3, wherein forming the first dielectric layer includes injecting aninorganic silicon compound.
 5. The method of claim 4, wherein injectingthe first metal source and injecting the inorganic silicon compound areperformed repeatedly, and a number of times the first metal source isinjected is greater than a number of times the inorganic siliconcompound is injected.
 6. The method of claim 4, wherein the inorganicsilicon compound is a halide silicon compound including at least oneselected from the group consisting of SiCl₄, SiCl₆, SiCl₂H₄, SiF₄ andcombinations thereof.
 7. The method of claim 4, wherein forming thesecond dielectric layer includes injecting an organic silicon compound.8. The method of claim 7, wherein injecting the second metal source andinjecting the organic silicon compound are performed repeatedly, and anumber of times the second metal source is injected is greater than anumber of times the organic silicon compound is injected.
 9. The methodof claim 7, wherein the organic silicon compound is a compound havingalkyl amino group including SiH_(n)(NR₁R₂)_(4-n) (wherein 0≦n<4), and R₁and R₂ are each independently at least one selected from the groupconsisting of an alkyl, an allyl and combinations thereof.
 10. Themethod of claim 3, wherein forming the second dielectric layer includesinjecting an organic silicon compound.
 11. The method of claim 10,wherein injecting the second metal source and injecting the organicsilicon compound are performed repeatedly, and a number of times thesecond metal source is injected is greater than a number of times theorganic silicon compound is injected.
 12. The method of claim 10,wherein the organic silicon compound is a compound having alkyl aminogroup including SiH_(n)(NR₁R₂)_(4-n) (wherein 0≦n<4), and R₁ and R₂ areeach independently at least one selected from the group consisting of analkyl, an allyl and combinations thereof.
 13. The method of claim 1,wherein the first metal source and the second metal source include asame metal.
 14. The method of claim 13, wherein forming the firstdielectric layer includes injecting an inorganic silicon compound. 15.The method of claim 14, wherein injecting the first metal source andinjecting the inorganic silicon compound are performed repeatedly, and anumber of times the first metal source is injected is greater than anumber of times the inorganic silicon compound is injected.
 16. Themethod of claim 14, wherein the inorganic silicon compound is a halidesilicon compound including at least one selected from the groupconsisting of SiCl₄, SiCl₆, SiCl₂H₄, SiF₄ and combinations thereof. 17.The method of claim 13, wherein forming the second dielectric layerincludes injecting an organic silicon compound.
 18. The method of claim17, wherein injecting the second metal source and injecting the organicsilicon compound are performed repeatedly, and a number of times thesecond metal source is injected is greater than a number of times theorganic silicon compound is injected.
 19. The method of claim 1, whereinthe carbon concentration in the first dielectric layer is the highest ata central portion thereof and lower at both edges thereof.